Process and apparatus for the uninterrupted production of alkaline azids



J. MEISSNER Aug. 22, 1933.

PROCESS AND APPARATUS FOR THE UNINTERRUPTED PRODUCTION OF ALKALINE AZIDS Filed Sept. 29, 1931 J77 ass/46w m/ycvv Fm? W H'HVX.

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Patented Aug. 2a, 1933 I i ,enocnss Am)- APPARATUS FOR THE NrN- a. :PRQDUCTION 10F. ALKALINE TERRUPTED Arms I Application Heretofore alkaline azids have been produced I shall now describe by way of example the production of sodium azid. yll/Ietallic sodium .is charged into a reactionvessel and heated to a temperature between 350 and 360 C. Ammonia gas is Now sodium amide and hydrogen is formed-according to the formula However at the beginning the sodium amide is formed very slowly, so that the complete reaction may take up "from 8 to 10 hours in the event of charges from 10 to 15 kilogrammes. Further the ammonia gas has to be passed through the molten sodium for 1 to 2 hours before the reaction commences and usually this ammonia gas is lost.

The reaction is accelerated whenever the production of sodium amide has commenced and increases in accordance with the increasing formation of sodium amide. Experiments have shown that three quarters of the reaction period is necessary for forming the first 50%, of sodium amide, while only aquarter of the reaction period is required for forming the remain ing 50% of sodium amide. I

After'the sodium amide is formed, the charge is fed into a reaction-mill in which a temperav at the same time ture of 160 to 180 C. is maintained. The product is agitated and broken up in the mill and nitrogen monoxide is introduced to cause the following reaction:--

The reaction of thesodium amide into sodium azid and sodium hydroxide in the reaction will by means of nitrogen monoxide proceed very slowly and calls for a great expenditure of nitrogen monoxide in the event of arc-interrupted process and if the whole charge is introduced and subjected to the reaction at a time. In the event of a charge of 20 to 25 kilogrammes sodium amide, the transformation into sodium azid needs 10 hours in the most unfavourable case. From S to 10 hours are necessaryfor the transformation even if smaller quantity of 8 I to 10 kilogrammes are employed. This slow re,-

action calls for an excessive quantity of nitrogen monoxide, heating material and amount of work. I I

It has been discovered, that the interruptions of reaction and the loss of time, which are unavoidable in the case of the interrupted process,

I Josef Meis'snei', Burbach, Germany Y i f Q 4 September 29, I I 565,914, and in Germany November '10, 1930 2 Claims. (01. 23-491)- introduced into I the melt whenever this temperature is, reached.

leaves the reaction-tank and subsequently is -tions or balls and amide'which already is in the and has been transformed in sodium azid, so

pletely transformed,

by way of example on the accompanying sheet 1931, Serial N55 can be avoided when 'uninterruptedly carrying out the process. 4 In order to attain this object, the molten sodium is uninterruptedly fed into a reactiontank for the production or sodium azid. In the course of its passage through the apparatus, the sodium mixes with thefinished sodium amide and within. 10 minutes is transformed into sodium amide by means ofintroduced ammonia gas. The reason for this extremely quick reac- 5 tion is the continuous presence of to'95 parts of finished sodium amide and of 10 to 5. parts of molten sodium only. I

The speed and direction or" flow through'the tank is controlled by suitable obstructions. The 9 finished molten sodium amide continuously introduced into a reaction drum 'mill, in which theproduct is broken up by suitable obstrucis transformed into sodium 75 azid, sodium" hydroxide by means of nitrogen monoxide. V v I The drum is constructed in such" a manner, that sodium azid and nitrogen monoxide are uninterruptedly supplied, whilesodium amide, sodium hydroxide andthe waste gases are uninterruptedly discharged. Also in this case the reaction is carried out within a very short time (about 10 minutes) becauseonly small quanti ties of sodium azid are .Jadmitted to sodium,

state of reaction that a very high output can be attained with a small apparatus. I 1 v The advantages of the new process, compared 19. with the known processes, are: i a s 1. Interruption of the production at any time, 2. Saving of raw materials because ammonia gas and nitrogen monoxide are practically com- 3. Saving of heating material because a long heating for starting the reaction is not necessary owingto the rapid reaction, I 4. Greatest efficiency with a very small apparatus, Y I

I 5. Saving of wages and power. I j

An apparatus for carrying out the process according to the present invention is illustrated of drawing in which:- a .1

Fig. 1 shows in sectional elevation a sodium amide'tank A and a drum mill B for the pro-,

' duction of sodium azid,

Fig. 2 shows in cross section the reaction drum n 0 mill and a discharge carriage.

for the finished sodium agitator-ribs, 15 the l 'igv 3 is a plan View of the amide tank. In Fig. 1 designate 1 the inlet for the molten sodium, 2 the inlet for the ammonia gases, 2

the plates for distributing the ammonia gases,

3 the outlet for the waste gases, 4 the outlet amide, 5 a bafiie plate,

6 the heater, 7 the inlet for admitting the sodium amide to the drum, 8 the inlet for the nitrogen monoxide, 9 a valve-controlled outlet for the discharge of sodium azid-sodium hydroxide, 10 the outlet for a stepped innerdrum, 11 11 the material under treatment, 11 the grinding balls, 12 the outer drum'with heater and 13 the operating gear. In Fig. 2 designate 14 discharge carriage, 11? sieves of the grinding steps and ll 'the sieves of the discharge steps. I claim:

7 1. Process for the uninterrupted production ofalkali az'idsby the uninterrupted production the ammonia gas, 11.; sieves in the latter;

said tank baifie plates and a heater in the tank, said tank having an inlet for the admission of the liquidalkali metal and separate passages for the ad- Imissi'on of ammonia, pipes in the tank for the discharge of the waste gases, a ball-mill for the transformation of the alkali amide into alkaliazid, and an overflow passage connecting the alkali former into the latter.

amide from the JOSEF MEISSNER.

with said mill for the discharge of its 

